DE69509777T2 - OBJECTS OF IDENTIFICATION OF OBJECTS WHEN THEIR SURFACE IS MAKED ROUGH AND THIS ROUGHNESS IS CHECKED AND ITS SUITABLE ITEMS - Google Patents

Abstract

The invention relates to a procedure for identification of an object, based on forming and verifying its surface roughness, in which a marking that makes its surface rough will be produced on the object and the picture and/or the code of the marking, preferably together with other identification data of the object, will be stored in the storage of a computer and/or on a portable storage means and, when identifying, the picture and/or the code of the marking placed on the object will be compared to those/that stored. The characteristic feature of the procedure is that, the 3-dimension marking containing the elementary formations of roughness in a chaotic arrangement will be produced by means of a printing surface processed by using stochastic electro-erosion and/or by means of stochastic electro-erosion. The invention also relates to an object suitable to be identified, provided with a marking produced according to any of the claims 1 to 7 and/or by means of other physical- and/or chemical way on its optically accessible surface. The novelty of the invention is that, the elementary formations of the surface roughness are of chaotic arrangement.

Description

[0001] The invention relates to a method for the identification of objects and an object intended for this purpose.

[0002] A number of different solutions have long existed for the protection against counterfeiting of objects such as seals for securing goods, bar codes, banknotes, credit cards, official documents, certificates, transport tickets, lead seals, machines such as means of transport and military equipment. However, the solutions that are becoming known only offer protection against counterfeiting until the counterfeiters find a more advanced technology that can reproduce the protective markings and recognize and copy the secret security code.

[0003] The patent literature describes several solutions, by which hidden markings are placed on the surface of the objects using different methods. For example, the specification of patent no. US 4,988,126 describes a method for the subsequent marking of embossed documents using luminescent components in the high/convex and/or deep/concave areas, which gives the relief print a stereoscopic reflection feature that can be checked by eye or with an appropriate device. This enables the verification of the documents for alteration or falsification in a simple way. This solution requires a special marking, which in each case must be adapted to the content of the document. Moreover, it can only be used for documents.

[0004] WO91/14217 and EP-A-0 252 842 deal with a corresponding method for engraving for the production of water-marked paper. In WO91/14217, the values of an image are converted into numerical form and later converted into a continuous surface. The level lines of said surface are drawn so that they result in a continuous engraving. In EP-A-0 252 842, the values of a black and white image are recorded according to the gray levels of the pixels and are automatically engraved with an electrode, the depth of the engraving being dependent on the gray levels.

[0005] EP-A-0 322 301 and BE-A-0 837 841 are related to the production of engravings in steel elements. In particular, EP-A-0 322 301 deals with the production of fine-cut printing tools which are produced by engraving in copper as a negative electrode, and the image engraved in the copper electrode is created by spark erosion in a steel element. In BE-A-0 837 841 the image on the electrode is produced by photo engraving.

[0006] CH-A-0 652 058 describes a device for the production of electrical discharges for cutting metal.

[0007] The aim of this invention is to provide such a solution that is able to prevent counterfeiting or to make it detectable and can be applied to different objects using relatively simple technologies, whereby false copies cannot be made even in the case when the indications of the application have become known.

[0008] The object is achieved with a method as described in claims from 1 to 5 and an object as described in claim 10.

[0009] Advantageous additions are included in the subclaims.

[0010] One of the principles of the invention is based on the recognition that if the 3D marking which gives a certain roughness on the surface and whose elementary formations are in chaotic order is produced using a stochastic process, the marking thus produced will not be reproducible with complete identity.

[0011] Consequently, if such a mark is applied to the surface of an object by means of stochastic processes, this mark will be able to mark the object in a distinctive manner. In this case, the object itself may be the object to be protected, or even a printing plate or stamp capable of applying marks to different objects in a documented manner. Such marks can be produced when an area of the object is treated with the stochastic effects of electroerosion.

[0012] In this case, electroerosion is defined as a continuous modification of any surface by means of particles with electrical charge, while stochastic electroerosion consists of all electroerosion processes in which the joint action between surface and particles is regulated by random events.

[0013] After further detection, the stochastic effects appear to the greatest extent in each electrical arc, which tears a crumb from the surface with the concentrated high energy effect of a discharge lasting less than a nanosecond. This phenomenon occurs when electrical contacts are opened, but after further detection, is best realized with electroerosion.

[0015] According to a further point of view, the identification of the objects is based on the design and checking of its surface roughness, with the process steps in which a 3-dimensional marking is produced on the object, which roughens its surface, the recognition data of the produced 3-dimensional marking are recorded, the recorded recognition data of the 3D marking are stored in a storage device and the stored recognition data are compared with the recognition data of a marking on the object, whereby the elementary formations of the surface roughness of the 3D marking are in a chaotic arrangement, and they are produced by stochastic electroerosion or a printer surface treated with stochastic electroerosion.

[0016] According to a further condition, electric discharge machining is implemented by an electric discharge machining device.

[0017] According to another aspect of the invention, the parameters of the electroerosion device are set as follows: reactive voltage 60 to 100 V, peak current values: 6 to 25 A, pulse width: 50 to 800 us, pause between pulses 10 to 800 us.

[0018] One or each of the adjustable parameters of the electric discharge machine is controlled by a generator. Random or quasi-random generator is used.

[0019] After a further inspection, the marking is applied to a printing stamp. The marking on the printing stamp can be printed on documents, metal plates, metal strips and/or plastic plates containing other information and the print is covered with transparent material if necessary.

[0020] According to another view, the marking is applied to the objects in their finished state, such as on sealed packaging or installed components.

The image and/or code of the marking is created using video recording and/or autotrophic and/or parametric optics. The image and/or code of the marking can also be created using an interferometer.

[0021] If the difference between the code of the last mark made and the mark made before last exceeds the tolerances applied, the printing plate/stamp is changed or the changes in the code are documented. The printing area containing the mark is reworked during the renewal.

[0022] Furthermore, according to the present invention, an object suitable for identification is produced, wherein its optically accessible surface is modified by chemical and/or physical methods in such a way that the elementary formations of the surface roughness are in a chaotic arrangement.

[0023] Another condition for the object is that the mark has cavities, craters, caves and channels that arise from the chaotic arrangement. The size of the elementary formations is 0.1 to 30 µm.

[0024] A significant advantage of this invention is that it can be applied to the surface of different objects so that counterfeiting is detected or prevented and the marking itself and its code and/or image can be produced, identified and stored using simple, reliable methods.

[0025] A further advantage of the invention is that even if a counterfeiter were able to read the code and marking localize, it would be impossible to reproduce them exactly with the current state of technology. To do this, it would be necessary to be able to control the electroerosion process within a nanosecond. The imitation of the chaotic arrangement can be discovered and checked by analyzing distribution functions. If there is an attempt at forgery, for example with microlaser technology, the melting marks left by the laser could be easily detected. In addition, microlaser technology cannot work on metallic surfaces with a resolution of less than 10 um.

[0026] The printing plates manufactured according to the invention and their use as markings can not only be used to provide packaged goods with individual markings, but also banknotes, credit cards, official documents, certificates, transport tickets and metal seals can be provided with them, thus making them forgery-proof. They can also be used on metal strips inserted into securities. The markings can be documented from time to time, and thus the objects suitable for identification can also be identified immediately by different methods if necessary.

[0027] A further advantage is that the effect of the electric arc can be further increased by its stochastic character, controlled by all controllable parameters by means of a random or quasi-random generator.

[0028] This solution has the further advantage that the characteristic elementary formations can be as small as 0.1 µm in size, and this means that the markings can be hidden practically invisibly on very fine surfaces. However, in such cases, ultraviolet optical systems or optical interferometers are necessary to produce the image.

[0029] The further advantages and possible applications of the invention are illustrated by examples. However, we must note that further possible applications exist beyond those illustrated.

Example 1:

[0030] A stamp is made for additional marking of packaged goods so that the tampering of the seal can be detected. The stamp is made of K1 quality steel, hardened to HRC 60, shaped like a cylinder with a diameter of 8 mm, the marking is placed on one of the end plates. The machining parameters of the electroerosion unit are set as follows:

- Reactive voltage: 60 to 100 V, preferably 80 V;

- Peak current values: 6 to 25 A;

- Pulse width: 50 to 800 us;

- Pause between pulses: 50 to 800 us.

[0031] In this case, the above-mentioned parameters of electric discharge machining can be set in four to five rough steps, with the possibility of fine adjustment within the rough steps. Each parameter is controlled by a random or quasi-random generator, the output of which controls the rough steps of the given parameters. Fuel oil, petroleum, transformer oil, kerosene or any SOE oil derivative or the mixture of them can be used as a dielectric for the electric discharge machining.

[0032] The electroerosion process should take 1 to 20 minutes. The final print surface contains cavities, craters, channels in a random arrangement. The resulting print surface is marked as A.

[0033] Another printing surface is manufactured under the same conditions, which is marked as B.

[0034] Using the printing surfaces, the sheet of the metal insert of the closure seal, which has printed text, is marked and the metal strip is covered with plastic film using a known method and, finally, the seals are applied to the packaging using a known method.

[0035] In the next step, the image of the marks A and B on the seals is recorded using a video recorder. Any other characteristic parameter of the series of goods can be stored in the same memory location.

[0036] When the given product is identified, the video image applied to the closure seal and the video code of the marking are compared with the values stored in the computer using a known method.

[0037] The events of Example 1 are shown in the figures below:

Fig. 1 shows the video image A

Fig. 2 shows the video image B

Fig. 3 shows the video code A

Fig. 4 shows the video code B.

[0038] Figures 1 and 2 show the video images at a tenfold magnification. In our case, no difference can be seen with the naked eye. However, since stochastic processes take place during electroerosion, visible differences can also arise if the above procedure is repeated.

[0039] The video codes shown in Figures 3 and 4 are also different in our case. This makes it possible to distinguish between the sealing seals printed with stamps A and B.

[0040] If any of the printing surfaces wear out, it will undergo certain changes. By documenting the changes, the printing surface remains usable. With a new printing surface treated with electroerosion, the old printing surface can be replaced, or the worn printing surface can be used, after appropriate Documentation of the changes. With appropriate documentation, this is not a disadvantage, but an advantage, because it creates further difficulties for counterfeiters.

Example 2:

[0041] A car component is marked as described in Example 1. For this purpose, a mass-produced component to be installed or a component that has already been installed can be used.

[0042] The video code of the marking is created and stored in a computer, with other data of the car.

[0043] Some parts of the car are marked and their video code, together with other identification data of the car, is stored on a magnetic or chip card and attached to the vehicle registration document. The identification is carried out using a known method.

[0044] Example 1 shows that the printing plates do not become the same even under the same conditions. The probability that images A and B become the same is 10-19 or less. It has also been proven that the markings printed on metal strips can be identified using simple video technology and comparing the video codes in the computer.

[0045] The method described in Example 2 can provide conductive, metallic parts of machines such as vehicles, military equipment and objects with forgery-proof markings. It enables the appropriate documentation of the markings and is capable of identifying the objects using different methods.

[0046] In the above examples, the average roughness of the markings is about 10 µm. The size of the formations varies between 0.4 and 15 µm. This size can be controlled by the choice of the material of the printing plate and/or the electrode and/or the parameters of the electroerosion device. By reducing the pulse width and/or the pause between the pulses to below 50 µs, advantageously between 10 and 50 µs and/or by reducing the peak current to below 6 A, advantageously between 2 and 6 A, the lower limit of the size can be reduced to below 0.4 µm. In this way, the space required by the markings can be further reduced, which makes recognition by third parties even more difficult. In such cases, the image and/or code of the markings can no longer be captured using video technology that operates in the visible range of light; However, with the use of an ultraviolet camera or other methods such as optical interferometers and/or autotrophic and/or parametric optics, the problem can be solved.

Example 3

[0047] Using the above techniques, the bits of keys can be marked. In the lock, a An optical reading unit is housed which is able to recognize the stochastic drawings produced by electroerosion and a microprocessor-controlled device for the comparison and identification of the code.

[0048] When the key is inserted into the lock, the optical unit reads the marking on the bit of the key, activating the identification unit which, based on its algorithm, compares the previously stored data with those read. If the two markings are the same, i.e. their digital sequences match, the lock is opened, otherwise it remains closed.

[0049] In addition to the electroerosion device, other methods can also be used to produce the markings, e.g. electrolysis, pulses with an amplitude that exceeds the arc voltage, or in electric plasma.

[0050] Furthermore, it must be noted that the markings according to the invention in a chaotic arrangement can be produced not only by electroerosion but also by other physical and chemical methods, e.g. corrosion or milling.

[0051] The marking on the printing stamp can be printed on different materials, such as paper, metal plate, metal strip, plastic plate; furthermore, the printed marking can be protected from counterfeiting by covering it with transparent material.

[0052] It is advantageous if the image and/or code of the marking is applied to the object already in its corresponding function, such as built-in components or sealed goods. In fact, under such circumstances the probability is greatest that the same results will be achieved if the images and/or code are repeatedly produced.

[0053] It will be a further advantage if the quality of the printing stamp can be monitored on the basis of the changes in the marks printed with it. In this way, if the code of the last printed mark exceeds the acceptable tolerances when compared with the one printed the second last time, it means that the printing stamp is worn out. In this case, the printing stamp can be reused or a new stamp can be used. Worn printing plates can be renewed by remachining the printing surface, e.g. by electroerosion.

Claims (11)

1. Method for identifying an object based on its design and checking its surface roughness, with the following process steps: Creating a 3-dimensional marking (A, B) on the object, which roughens its surface, Recording recognition data of the generated 3-dimensional marking (A, B), Saving the recorded recognition data of the 3-dimensional marking (A, B) in a storage device, Comparing the recognition data of a marking on an object with the stored recognition data, characterized in that the elementary formations of the surface roughness of the 3-dimensional marking (A, B) are in a chaotic arrangement. 2. Method for identifying an object according to Claim 1, in which the 3-dimensional marking (A, B) is produced by stochastic electro-erosion. 3. Method for identifying an object according to claim 2, with the further step of setting adjustable process parameters of the stochastic electro-erosion blind: voltage = 60 to 100 V, peak values of the current = 6 to 25 A, pulse width = 50 to 800 us and pause between the pulses = 10 to 800 us. 4. Method for identifying an object according to claim 3, with the further step of randomly checking the adjustable method parameters with the aid of a random or quasi-random generator. 5. Procedure for identifying an object based on the design and inspection of its surface with the following process steps: Creating a 3-dimensional mark on the object, which roughens its surface, Recording recognition data of the produced 3-dimensional marking (A, B), Saving the recorded recognition data of the produced 3-dimensional marking (A, B) in a storage device, Comparing the detection data of a mark on an object with the stored data characterized in that the 3-dimensional marking of a printing plate is created, whereby the elementary formations that make up the surface roughness of the 3-dimensional marking (A, B) are in a chaotic arrangement. 6. Method for identifying an object according to claim 5, characterized in that the 3-dimensional marking (A, B) created on the printing plate is optionally printed on paper, metal plate, metal strip or plastic plate, which may also contain other information, and the print is optionally covered with transparent material. 7. Method for identifying an object according to claims 1 to 6, characterized in that the code of the 3-dimensional marking (A, B) is created with a video recorder or an autotrophic or parametric optics. 8. Method for identifying an object according to claims 1 to 7, characterized in that the code of the 3-dimentional marking (A, B) is created with an optical interferometer. 9. A method for identifying an object according to claim 4 or 5, characterized in that if the difference between the last code of the 3-dimensional marking (A, B) produced with the printing plate and the code of the previous marking (A, B) exceeds the limits used, the printing plate is changed or the changes are documented in the code. 10. An object with a surface suitable for identification, which has a 3-dimensional marking (A, B) on its optically accessible surface, which has been produced by means of a physical and/or chemical process and changes the surface roughness of the object, characterized in that the elementary formations of the surface roughness of this 3-dimensional marking (A, b) are in a chaotic arrangement. 11. Article according to claim 10, characterized in that the size of the elementary formations of the surface roughness is between 0.1 µm and 30 µm.